The present invention relates to laboratory techniques and equipment for drying flat gel slabs following electrophoretic separations. In particular, this invention relates to the fixing of gels and the position of the bands therein for purposes of preservation and accurate analysis of the electrophoretic pattern.
Existing devices for the fixing of gel slabs by dehydration generally use both heat and vacuum to vaporize the moisture from the gel. One of several examples in the published literature of such a device is that disclosed in Hoefer, U.S. Pat. No. 4,020,563 (issued May 3, 1977).
The drying of a gel is made difficult by the fact that the gel vitrifies upon drying to a brittle solid impervious to fluid. Thus, when localized heating or vaporization dries a surface or region of a gel slab, moisture in the adjacent regions must find its way around the dried areas in order to escape. Frequently, the moisture can become trapped inside the gel. As the trapped moisture vaporizes and continues to expand, the pressure inside the gel increases and lateral stresses arise, causing the drying gel to crack. In addition, when minute cracks appear, they expand rapidly as the pressurized entrapped vapor seeks release.